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Minerals and Gems

Grinding is a particularly simple example of physical processing. It has been used to make pigments, early cosmetics, and the ingredients for the potter s slip. It is a key step in modern ore processing (Chapter 19), but it has been used for centuries to make powders. [Pg.652]

Grind cinnabar to produce the major component of Vermillion [Pg.652]

Pele s hair (the Hawaiian goddess of volcanoes, not the soccer player) consists of natural threads of basalt glass often containing crystals of olivine. Like obsidian and pumice it forms in volcanic eruptions. [Pg.652]

Crush lapis lazuli like the Persians did to make [Pg.652]

Grind azurite like the ancient Egyptians to produce the blue pigment azure [Pg.652]

Ray, Mira. Minerals and gems in Indian alchemy. Indian J Hist Sci 26 (1991) 133-154. [Pg.450]

Many crystalline materials, especially minerals and gems, were described more than 2000 years ago. The regular form of crystals and the existence of facets, which have fixed angles between them, gave rise to... [Pg.27]

See other pages where Minerals and Gems is mentioned: [Pg.39]    [Pg.554]    [Pg.47]    [Pg.47]    [Pg.1166]    [Pg.34]    [Pg.141]    [Pg.652]    [Pg.652]    [Pg.654]    [Pg.656]    [Pg.658]    [Pg.662]    [Pg.663]    [Pg.663]    [Pg.664]    [Pg.666]    [Pg.668]    [Pg.670]    [Pg.670]    [Pg.671]    [Pg.672]    [Pg.674]    [Pg.652]    [Pg.652]    [Pg.654]    [Pg.656]    [Pg.658]    [Pg.660]    [Pg.662]    [Pg.663]    [Pg.663]    [Pg.664]    [Pg.666]    [Pg.668]    [Pg.670]    [Pg.670]    [Pg.671]    [Pg.672]    [Pg.674]   


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